In commerce and industry today, the useful life of corrodible items may be extended and/or preserved by providing corrosion inhibitors which protect the corrodible item from the adverse effects of its ambient environment. Among the common indications of corrosion manifested in useful metallic articles are oxidation, pitting, tarnishing, mottling or discoloration of the surfaces of these items. These manifestations occur in metallic articles, particularly when exposed to oxygen, water or other corrosive environments, in either gaseous or liquid phase. Additionally, sulfides and/or chlorides (or chlorine) may cause corrosion or tarnishing problems as well. In as much as both oxygen and water, including water vapor, occur normally and are available in nature, it is normally necessary to take precautions against corrosion in a variety of metallic based containers, shippers, storage tanks, tanker ships, gas tanks, septic systems (including the tank), etc. Metals which are frequently found to be susceptible to corrosion under normal atmospheric and ambient conditions include, but are not limited to, iron, copper, brass, aluminum, silver, and alloys of these metals.
In view of the widespread need for protecting various metallic based tanks, containers, semi-closed systems, and/or closed systems from corrosion, a variety of systems have been utilized. Such anti-corrosion systems often employ one or more of the following as components or sub-components thereof: (1) a cathodic protection system; (2) a liner system which coats the inside of the tank, container and/or closed system and/or (3) an inert atmosphere.
Such methods, although effective, are not suitable for all tanks, containers, pipelines and/or closed systems which may need to be protected. Additionally, such methods have service lives which are not suitable for applications in which a long service life is necessary, for example, the use of cathodic systems to protect the cargo tanks of ocean liners which carry petroleum products. Furthermore, the replenishment of certain currently used systems, such as cathodic systems, is both expensive and difficult.